This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. There is an unmet need for effective, efficient, and economical methods for conducting AD prevention trials. Traditional in-person visits to clinical assessment sites are time consuming and costly and may exclude some people from participation, such as those who are older, or are less mobile or with significant medical illnesses.These may be the people who are at greatest risk for cognitive decline, and also may be without financial resources for services such as transportation to a study site. Prevention trials require long observation periods and these same issues of health, resources, and transportation may cause significant drop out. These obstacles increase expense of clinical trials which require large sample sizes, costly clinical staff and long observation periods. Thus, home-based assessments may lead to more representative recruitment of those most at risk for decline, as well as better retention and reduced study costs. This is a randomized study of 600 participants, comparing three methods of test administration and data collection. Each enrolled participant will have an In-person (Standard) assessment (in the clinic or at home) prior to baseline. Participants will be classified as either normal or MCI (Mild Cognitive Impairment) and randomly assigned to an assessment method and to a frequency of assessment. Cognitive performance, self-rated cognitive complaint, functioning in daily life, affective symptoms, global change, quality of life and resource use will all be assessed in each method at each visit. The total time for the at-home assessments will be approximately 45 minutes. In addition, all participants will be provided a multi-vitamin to be taken twice a day, and a measure of medication adherence will be collected for each assessment method. Changes in certain cognitive measures may "trigger" an in-person assessment, in which participants may change from a categorization of normal or amnestic MCI, to non-amnestic MCI, impaired not MCI, or dementia (i.e., specifically Alzheimer's Disease or another dementia). We estimate that 12% of the study population will trigger over the 4 years of the study and will progress to a more impaired diagnostic category. In addition, a random sample of non-triggered cases (25%) will be selected for an in-person re-assessment during the 4 years of the protocol as a comparison for the trigger group. At the end of the 4-year study period all participants will undergo an in-person evaluation.